The devices described below relate to the field of surgical devices and methods, specifically to the field of endoscopic suturing techniques.
BACKGROUND OF THE INVENTIONS
Sutures and stitching are well known techniques for repairing body tissue after injury or surgery. Many types of surgery, such as gall bladder removal, hernia repair, and even coronary bypass surgery can now be performed through the techniques of endoscopic surgery. Endoscopic surgery, also referred to as laparoscopic surgery, minimally invasive surgery, or bloodless surgery, is performed through small incisions in the body with long slender cutting and grasping devices which can be inserted into the body through the small incisions. The devices have small working mechanisms on the distal end (the end of the instrument that is inserted into the body) and convenient handles and operating mechanisms (for controlling the working mechanisms on the proximal end). Surgeons use endoscopic scalpels and scissors for cutting tissue, endoscopic graspers and forceps for grabbing and manipulating tissue, and endoscopic suture needles for stitching tissue. Stitching a surgical or traumatic wound closed within an endoscopic work space requires quite a bit of manual dexterity and experience, and the final process of tying a knot in the stitching is very difficult.
Several devices have been suggested for assisting surgeons in securing the loose ends of a suture during open surgery. Rather than assisting the surgeon to tie a knot, the devices allow the surgeon to melt the two loose ends of the suture together or to create a melted mass on a single loose suture tip which prevents it from being withdrawn into the suture pathway. Zinnbauer, et al, Suture Cutting and Cauterizing Method Using Radiant Heat, U.S. Pat. No. 5,565,122 (Oct. 15, 1996), while not intended or adapted for endoscopic use, shows a device with jaws mounted at the distal end of a long neck, and a heating element over the jaws. When the jaws are laid against the skin, and the suture is place between the jaws, the heating element is heated to melt the suture and leave a melted mass of suture material on the suture. The melted mass prevents the suture from being pulled into and through the suture line. Polonsky, Suture Fusing and Cutting Apparatus, U.S. Pat. No. 4,662,068 (May 5, 1987) shows a pair of forceps with heat fusing surfaces on the grasping surfaces of the jaws. The forceps are used to grab and twist two loose suture ends and melt them together to secure the stitching.
The devices and methods described below permit the closure of stitches during endoscopic surgery. The devices are endoscopic tools capable of insertion into an endoscopic access port, such as a cannula, and include a long slender insertion rod with a handle and operating mechanism on the proximal end and a pair of grasping jaws on the distal end of the rod. The grasping jaws are fitted with heating surfaces which can be heated to temperatures sufficient to melt suture. A snare comprised of a snare portion and a rod is housed within the insertion rod. The snare portion can be pushed out the distal end of the insertion rod and manipulated to snare a length of suture and then pulled proximally into the insertion rod. The snare may be twisted to create a length of twisted-together suture. Because the snare is drawn into the insertion rod, the entrapped suture is pulled into the space between the jaws where it can be grasped and melted by the jaws. This provides an easy way to get the suture between the jaws with limited movement of the insertion rod within the body and the endoscopic access port. The suture may be tensioned as desired by the surgeon prior to melting by closing the jaws firmly on the suture while drawing the snare proximally, then closely the jaws tightly so that the suture is held in properly tensioned position while the weld is accomplished.
In one embodiment, the jaws can be scissor-like, having opposing grasping faces which meet to clamp the suture between the grasping faces. In another embodiment, the grasping faces are mounted on co-axially disposed tubes, where the tubes rotate relative to the each other to bring the grasping faces together and close upon the suture.
A composite weldable suture is described below which is particularly useful in the creating of melted knots. The suture t comprises a core, which melts at moderately high temperatures compared to a porous fiber cover, which melts at a high temperature. When two strands of suture are pressed together and exposed to heat, as in the operation of the suture welding devices, the cores melt and seep through the fiber cover and fuse together. The presence of the fiber provides structural integrity to the suture which ensures that the melted knot does not separate from the standing part of the suture.